CVE-2018-12893 Information

Description

An issue was discovered in Xen through 4.10.x. One of the fixes in XSA-260 added some safety checks to help prevent Xen livelocking with debug exceptions. Unfortunately due to an oversight at least one of these safety checks can be triggered by a guest. A malicious PV guest can crash Xen leading to a Denial of Service. All Xen systems which have applied the XSA-260 fix are vulnerable. Only x86 systems are vulnerable. ARM systems are not vulnerable. Only x86 PV guests can exploit the vulnerability. x86 HVM and PVH guests cannot exploit the vulnerability. An attacker needs to be able to control hardware debugging facilities to exploit the vulnerability but such permissions are typically available to unprivileged users.

CVSS Vector

CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Reference

http://www.openwall.com/lists/oss-security/2018/06/27/11 http://www.securityfocus.com/bid/104572 http://www.securitytracker.com/id/1041202 http://xenbits.xen.org/xsa/advisory-265.html https://bugzilla.redhat.com/show_bug.cgi?id=1590979 https://lists.debian.org/debian-lts-announce/2018/11/msg00013.html https://security.gentoo.org/glsa/201810-06 https://support.citrix.com/article/CTX235748 https://www.debian.org/security/2018/dsa-4236

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

6.5